Data circuit for a low swing data bus

ABSTRACT

Methods, systems, and devices for a data circuit for a low swing data bus are described. An apparatus may include a data bus that may transfer data at a first voltage different than a second voltage that is associated with one or more components of the memory array. A transistor, coupled with the data bus, may receive the second voltage and send a third voltage. A first in first out (FIFO), coupled with the transistor, may receive the third voltage from the transistor. The FIFO circuit may include one or more precharge components that drive an input voltage of the FIFO circuit to the second voltage associated with the one or more components of the memory array based on receiving the third voltage.

FIELD OF TECHNOLOGY

The following relates generally to one or more systems for memory andmore specifically to a data circuit for a low swing data bus.

BACKGROUND

Memory devices are widely used to store information in variouselectronic devices such as computers, user devices, wirelesscommunication devices, cameras, digital displays, and the like.Information is stored by programing memory cells within a memory deviceto various states. For example, binary memory cells may be programmed toone of two supported states, often denoted by a logic 1 or a logic 0. Insome examples, a single memory cell may support more than two states,any one of which may be stored. To access the stored information, acomponent may read, or sense, at least one stored state in the memorydevice. To store information, a component may write, or program, thestate in the memory device.

Various types of memory devices and memory cells exist, includingmagnetic hard disks, random access memory (RAM), read-only memory (ROM),dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM),ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM),flash memory, phase change memory (PCM), self-selecting memory,chalcogenide memory technologies, and others. Memory cells may bevolatile or non-volatile. Non-volatile memory, e.g., FeRAM, may maintaintheir stored logic state for extended periods of time even in theabsence of an external power source. Volatile memory devices, e.g.,DRAM, may lose their stored state when disconnected from an externalpower source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system that supports a data circuitfor a low swing data bus in accordance with examples as disclosedherein.

FIG. 2 illustrates an example of a memory die that supports a datacircuit for a low swing data bus in accordance with examples asdisclosed herein.

FIG. 3 illustrates an example of circuit that supports a data circuitfor a low swing data bus in accordance with examples as disclosedherein.

FIG. 4 illustrates an example of a timing diagram that supports a datacircuit for a low swing data bus in accordance with examples asdisclosed herein.

FIG. 5 shows a block diagram of a memory device that supports a datacircuit for a low swing data bus in accordance with examples asdisclosed herein.

FIG. 6 shows a flowchart illustrating a method or methods that support adata circuit for a low swing data bus in accordance with examples asdisclosed herein.

DETAILED DESCRIPTION

A system may include a memory device and a host device coupled with thememory device. In some examples, the host device may initiate an accessoperation (e.g., read operation, write operation) at the memory device.In such examples, the memory device may transfer data from a firstlocation to a second location in response to receiving the accessoperation, and the memory device may transfer the data over a bus. Insome examples, the memory device may be a high-frequency bus system(e.g., a graphics system such as a graphic double data rate system). Insome cases, the memory device may utilize limited swing signaling whentransferring data over the bus to reduce current consumption. That is,the memory device may transfer data at a voltage lower than a voltage(e.g., a full swing or full voltage) associated with one or morecomponents of a memory array in the memory device—e.g., CMOS circuitryor peripheral components that process or perform digital calculations onthe data. In such examples, the memory device may have to recover thelimited swing on the bus to operate the CMOS circuitry, which mayrequire relatively more power. For example, the memory device maytransfer data at the limited swing on the bus from a first location to adata circuit, such as a first in first out (FIFO) circuit. In suchexamples, the memory device may have to recover to the full swingvoltage to process (e.g. perform) digital calculations on the datareceived at the FIFO. In some examples, it may be difficult to recoverthe limited swing to the full swing—e.g., in a high-frequency bussystem. For example, recovering the limited swing may utilize additionalcomplicated CMOS circuitry and the memory device may consume more powerand require more current recovering the limited swing than the memorydevice conserves by utilizing the limited swing bus—e.g., the additionalCMOS circuitry may utilize a relatively high amount of power andcurrent. Improved swing operation for data circuits, such as FIFOcircuits, is needed.

As described herein, a memory device may utilize a FIFO circuit with asimple cell input (e.g., an n-type metal-oxide semiconductor transistor)and precharge the FIFO circuit to a full swing voltage before receivingthe data. For example, in a high-frequency system (e.g., a graphicssystem such as a graphics double data rate system) connecting differentregions of a chip (e.g., the memory device) over a distance (e.g., adistance on the order of millimeters), the memory device may utilize aFIFO circuit to securely transfer the data. The memory device may alsoutilize the FIFO circuit to correct for propagation delays due tolocally different voltages and respective delays. For example, the FIFOmay receive data from a first location with a first voltage and firstdelay (e.g., time scale or time domain) and receive data from a secondlocation with a second voltage and a second delay and generate an outputthat corrects the propagation delays. The FIFO circuit may receive thedata from a limited swing bus. By utilizing the simple cell input andprecharging the FIFO described in the present disclosure, the FIFOcircuit may recover the full swing voltage (e.g., the voltage associatedwith the one or more components of the memory array or VPERI) to processthe data. For example, the FIFO circuit may include one or moreprecharge components. The memory system may utilize a signal toprecharge the FIFO circuit to the full swing voltage before the FIFOreceives the data—the limited swing may automatically be recovered inthe FIFO circuit. In such examples, the memory device may conservecurrent by using the limited swing bus while also processing the data atthe FIFO, among other benefits.

Features of the disclosure are initially described in the context ofsystems and dies as described with reference to FIGS. 1 and 2. Featuresof the disclosure are described in the context of a circuit and timingdiagram as described with reference to FIGS. 3 and 4. These and otherfeatures of the disclosure are further illustrated by and described withreference to an apparatus diagram and flowcharts that relate to a datacircuit for a low swing data bus as described with reference to FIGS. 5and 6.

FIG. 1 illustrates an example of a system 100 that supports a datacircuit for a low swing data bus in accordance with examples asdisclosed herein. The system 100 may include a host device 105, a memorydevice 110, and a plurality of channels 115 coupling the host device 105with the memory device 110. The system 100 may include one or morememory devices 110, but aspects of the one or more memory devices 110may be described in the context of a single memory device (e.g., memorydevice 110).

The system 100 may include portions of an electronic device, such as acomputing device, a mobile computing device, a wireless device, agraphics processing device, a vehicle, or other systems. For example,the system 100 may illustrate aspects of a computer, a laptop computer,a tablet computer, a smartphone, a cellular phone, a wearable device, aninternet-connected device, a vehicle controller, or the like. The memorydevice 110 may be a component of the system operable to store data forone or more other components of the system 100.

At least portions of the system 100 may be examples of the host device105. The host device 105 may be an example of a processor or othercircuitry within a device that uses memory to execute processes, such aswithin a computing device, a mobile computing device, a wireless device,a graphics processing device, a computer, a laptop computer, a tabletcomputer, a smartphone, a cellular phone, a wearable device, aninternet-connected device, a vehicle controller, a system on a chip(SoC), or some other stationary or portable electronic device, amongother examples. In some examples, the host device 105 may refer to thehardware, firmware, software, or a combination thereof that implementsthe functions of an external memory controller 120. In some examples,the external memory controller 120 may be referred to as a host or ahost device 105.

A memory device 110 may be an independent device or a component that isoperable to provide physical memory addresses/space that may be used orreferenced by the system 100. In some examples, a memory device 110 maybe configurable to work with one or more different types of hostdevices. Signaling between the host device 105 and the memory device 110may be operable to support one or more of: modulation schemes tomodulate the signals, various pin configurations for communicating thesignals, various form factors for physical packaging of the host device105 and the memory device 110, clock signaling and synchronizationbetween the host device 105 and the memory device 110, timingconventions, or other factors.

The memory device 110 may be operable to store data for the componentsof the host device 105. In some examples, the memory device 110 may actas a secondary-type or dependent-type device to the host device 105(e.g., responding to and executing commands provided by the host device105 through the external memory controller 120). Such commands mayinclude one or more of a write command for a write operation, a readcommand for a read operation, a refresh command for a refresh operation,or other commands.

The host device 105 may include one or more of an external memorycontroller 120, a processor 125, a basic input/output system (BIOS)component 130, or other components such as one or more peripheralcomponents or one or more input/output controllers. The components ofthe host device 105 may be coupled with one another using a bus 135.

The processor 125 may be operable to provide control or otherfunctionality for at least portions of the system 100 or at leastportions of the host device 105. The processor 125 may be ageneral-purpose processor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or a combination ofthese components. In such examples, the processor 125 may be an exampleof a central processing unit (CPU), a graphics processing unit (GPU), ageneral purpose GPU (GPGPU), or an SoC, among other examples. In someexamples, the external memory controller 120 may be implemented by or bea part of the processor 125.

The BIOS component 130 may be a software component that includes a BIOSoperated as firmware, which may initialize and run various hardwarecomponents of the system 100 or the host device 105. The BIOS component130 may also manage data flow between the processor 125 and the variouscomponents of the system 100 or the host device 105. The BIOS component130 may include a program or software stored in one or more of read-onlymemory (ROM), flash memory, or other non-volatile memory.

The memory device 110 may include a device memory controller 155 and oneor more memory dies 160 (e.g., memory chips) to support a desiredcapacity or a specified capacity for data storage. Each memory die 160(e.g., memory die 160 a, memory die 160 b, memory die 160 N) may includea local memory controller 165 (e.g., local memory controller 165-a,local memory controller 165-b, local memory controller 165-N) and amemory array 170 (e.g., memory array 170-a, memory array 170-b, memoryarray 170-N). A memory array 170 may be a collection (e.g., one or moregrids, one or more banks, one or more tiles, one or more sections) ofmemory cells, with each memory cell being operable to store at least onebit of data. A memory device 110 including two or more memory dies 160may be referred to as a multi-die memory or a multi-die package or amulti-chip memory or a multi-chip package.

The device memory controller 155 may include circuits, logic, orcomponents operable to control operation of the memory device 110. Thedevice memory controller 155 may include the hardware, the firmware, orthe instructions that enable the memory device 110 to perform variousoperations and may be operable to receive, transmit, or executecommands, data, or control information related to the components of thememory device 110. The device memory controller 155 may be operable tocommunicate with one or more of the external memory controller 120, theone or more memory dies 160, or the processor 125. In some examples, thedevice memory controller 155 may control operation of the memory device110 described herein in conjunction with the local memory controller 165of the memory die 160.

A local memory controller 165 (e.g., local to a memory die 160) mayinclude circuits, logic, or components operable to control operation ofthe memory die 160. In some examples, a local memory controller 165 maybe operable to communicate (e.g., receive or transmit data or commandsor both) with the device memory controller 155. In some examples, amemory device 110 may not include a device memory controller 155, and alocal memory controller 165 or the external memory controller 120 mayperform various functions described herein. As such, a local memorycontroller 165 may be operable to communicate with the device memorycontroller 155, with other local memory controllers 165, or directlywith the external memory controller 120, or the processor 125, or acombination thereof. Examples of components that may be included in thedevice memory controller 155 or the local memory controllers 165 or bothmay include receivers for receiving signals (e.g., from the externalmemory controller 120), transmitters for transmitting signals (e.g., tothe external memory controller 120), decoders for decoding ordemodulating received signals, encoders for encoding or modulatingsignals to be transmitted, or various other circuits or controllersoperable for supporting described operations of the device memorycontroller 155 or local memory controller 165 or both.

The external memory controller 120 may be operable to enablecommunication of one or more of information, data, or commands betweencomponents of the system 100 or the host device 105 (e.g., the processor125) and the memory device 110. The external memory controller 120 mayconvert or translate communications exchanged between the components ofthe host device 105 and the memory device 110. In some examples, theexternal memory controller 120 or other component of the system 100 orthe host device 105, or its functions described herein, may beimplemented by the processor 125. For example, the external memorycontroller 120 may be hardware, firmware, or software, or somecombination thereof implemented by the processor 125 or other componentof the system 100 or the host device 105. Although the external memorycontroller 120 is depicted as being external to the memory device 110,in some examples, the external memory controller 120, or its functionsdescribed herein, may be implemented by one or more components of amemory device 110 (e.g., a device memory controller 155, a local memorycontroller 165) or vice versa.

The components of the host device 105 may exchange information with thememory device 110 using one or more channels 115. The channels 115 maybe operable to support communications between the external memorycontroller 120 and the memory device 110. Each channel 115 may beexamples of transmission mediums that carry information between the hostdevice 105 and the memory device. Each channel 115 may include one ormore signal paths or transmission mediums (e.g., conductors) betweenterminals associated with the components of the system 100. A signalpath may be an example of a conductive path operable to carry a signal.For example, a channel 115 may include a first terminal including one ormore pins or pads at the host device 105 and one or more pins or pads atthe memory device 110. A pin may be an example of a conductive input oroutput point of a device of the system 100, and a pin may be operable toact as part of a channel.

Channels 115 (and associated signal paths and terminals) may bededicated to communicating one or more types of information. Forexample, the channels 115 may include one or more command and address(CA) channels 186, one or more clock signal (CK) channels 188, one ormore data (DQ) channels 190, one or more other channels 192, or acombination thereof. In some examples, signaling may be communicatedover the channels 115 using single data rate (SDR) signaling or doubledata rate (DDR) signaling. In SDR signaling, one modulation symbol(e.g., signal level) of a signal may be registered for each clock cycle(e.g., on a rising or falling edge of a clock signal). In DDR signaling,two modulation symbols (e.g., signal levels) of a signal may beregistered for each clock cycle (e.g., on both a rising edge and afalling edge of a clock signal).

In some examples, the memory device 110 may use a high-frequency bussystem (e.g., graphics system such as a graphics double data ratesystem, a system with a clock period of 500 picoseconds or shorter). Insuch examples, the memory device 110 may utilize a FIFO to securelytransfer data from a first region of the memory device 110 to a secondregion of the memory device 110—e.g., from memory die 160-a to the FIFO.In some examples, the memory device 110 may also utilize a limited swingbus to transfer the data—e.g., the memory device 110 may use a voltagelower than a voltage (e.g., full swing voltage) associated with othercomponents of the memory device 110 to conserve power and currentconsumption. In some examples, the memory device 110 may have to recoverthe limited swing to the full swing to process and perform digitalcalculations on the data at the FIFO circuit. In some cases, therecovery may be difficult—e.g., adding additional CMOS circuitry torecover the limited swing may consume more power and current.

As described herein, the memory device 110 may utilize a simple cellFIFO circuit with precharge components. For example, the FIFO circuitmay include one or more transistors (e.g., an nMOS transistor) as aninput and include one or more precharge components. The memory device110 may precharge the FIFO to the full swing voltage by transmitting asignal to the one or more precharge components. The FIFO may thenreceive the data and process and store the data—e.g., the limited swingvoltage may automatically be recovered to the full swing voltage basedon precharging the FIFO circuit with the one or more precharge devices.In such examples, the memory device 110 may reduce the consumption ofpower and current with the limited swing bus while still being able toprocess the data at the full swing at the FIFO, among other advantages.

FIG. 2 illustrates an example of a memory die 200 that supports a datacircuit for a low swing data bus in accordance with examples asdisclosed herein. The memory die 200 may be an example of the memorydies 160 described with reference to FIG. 1. In some examples, thememory die 200 may be referred to as a memory chip, a memory device, oran electronic memory apparatus. The memory die 200 may include one ormore memory cells 205 that may each be programmable to store differentlogic states (e.g., programmed to one of a set of two or more possiblestates). For example, a memory cell 205 may be operable to store one bitof information at a time (e.g., a logic 0 or a logic 1). In someexamples, a memory cell 205 (e.g., a multi-level memory cell) may beoperable to store more than one bit of information at a time (e.g., alogic 00, logic 01, logic 10, a logic 11). In some examples, the memorycells 205 may be arranged in an array, such as a memory array 170described with reference to FIG. 1.

A memory cell 205 may store a charge representative of the programmablestates in a capacitor. DRAM architectures may include a capacitor thatincludes a dielectric material to store a charge representative of theprogrammable state. In other memory architectures, other storage devicesand components are possible. For example, nonlinear dielectric materialsmay be employed. The memory cell 205 may include a logic storagecomponent, such as capacitor 230, and a switching component 235. Thecapacitor 230 may be an example of a dielectric capacitor or aferroelectric capacitor. A node of the capacitor 230 may be coupled witha voltage source 240, which may be the cell plate reference voltage,such as Vpl, or may be ground, such as Vss.

The memory die 200 may include one or more access lines (e.g., one ormore word lines 210 and one or more digit lines 215) arranged in apattern, such as a grid-like pattern. An access line may be a conductiveline coupled with a memory cell 205 and may be used to perform accessoperations on the memory cell 205. In some examples, word lines 210 maybe referred to as row lines. In some examples, digit lines 215 may bereferred to as column lines or bit lines. References to access lines,row lines, column lines, word lines, digit lines, or bit lines, or theiranalogues, are interchangeable without loss of understanding oroperation. Memory cells 205 may be positioned at intersections of theword lines 210 and the digit lines 215.

Operations such as reading and writing may be performed on the memorycells 205 by activating or selecting access lines such as one or more ofa word line 210 or a digit line 215. By biasing a word line 210 and adigit line 215 (e.g., applying a voltage to the word line 210 or thedigit line 215), a single memory cell 205 may be accessed at theirintersection. The intersection of a word line 210 and a digit line 215in either a two-dimensional or three-dimensional configuration may bereferred to as an address of a memory cell 205.

Accessing the memory cells 205 may be controlled through a row decoder220 or a column decoder 225. For example, a row decoder 220 may receivea row address from the local memory controller 260 and activate a wordline 210 based on the received row address. A column decoder 225 mayreceive a column address from the local memory controller 260 and mayactivate a digit line 215 based on the received column address.

Selecting or deselecting the memory cell 205 may be accomplished byactivating or deactivating the switching component 235 using a word line210. The capacitor 230 may be coupled with the digit line 215 using theswitching component 235. For example, the capacitor 230 may be isolatedfrom digit line 215 when the switching component 235 is deactivated, andthe capacitor 230 may be coupled with digit line 215 when the switchingcomponent 235 is activated.

The sense component 245 may be operable to detect a state (e.g., acharge) stored on the capacitor 230 of the memory cell 205 and determinea logic state of the memory cell 205 based on the stored state. Thesense component 245 may include one or more sense amplifiers to amplifyor otherwise convert a signal resulting from accessing the memory cell205. The sense component 245 may compare a signal detected from thememory cell 205 to a reference 250 (e.g., a reference voltage). Thedetected logic state of the memory cell 205 may be provided as an outputof the sense component 245 (e.g., to an input/output 255), and mayindicate the detected logic state to another component of a memorydevice that includes the memory die 200.

The local memory controller 260 may control the accessing of memorycells 205 through the various components (e.g., row decoder 220, columndecoder 225, sense component 245). The local memory controller 260 maybe an example of the local memory controller 165 described withreference to FIG. 1. In some examples, one or more of the row decoder220, column decoder 225, and sense component 245 may be co-located withthe local memory controller 260. The local memory controller 260 may beoperable to receive one or more of commands or data from one or moredifferent memory controllers (e.g., an external memory controller 120associated with a host device 105, another controller associated withthe memory die 200), translate the commands or the data (or both) intoinformation that can be used by the memory die 200, perform one or moreoperations on the memory die 200, and communicate data from the memorydie 200 to a host device 105 based on performing the one or moreoperations. The local memory controller 260 may generate row signals andcolumn address signals to activate the target word line 210 and thetarget digit line 215. The local memory controller 260 may also generateand control various voltages or currents used during the operation ofthe memory die 200. In general, the amplitude, the shape, or theduration of an applied voltage or current discussed herein may be variedand may be different for the various operations discussed in operatingthe memory die 200.

The local memory controller 260 may be operable to perform one or moreaccess operations on one or more memory cells 205 of the memory die 200.Examples of access operations may include a write operation, a readoperation, a refresh operation, a precharge operation, or an activateoperation, among others. In some examples, access operations may beperformed by or otherwise coordinated by the local memory controller 260in response to various access commands (e.g., from a host device 105).The local memory controller 260 may be operable to perform other accessoperations not listed here or other operations related to the operatingof the memory die 200 that are not directly related to accessing thememory cells 205.

FIFO 265 (e.g., the FIFO cell 265-a and FIFO cell 265-b may becollectively referred to as FIFO 265) may be configured to receive datafrom the sense component 245. It should be noted two FIFO cells (e.g.,the FIFO cell 265-a and FIFO cell 265-b) are shown for illustrativepurposes only. That is, the FIFO 265 may include more than two FIFOcells (e.g., three, four, five, six, seven, eight, nine, or more FIFOcells). In some examples, the FIFO 265 may be inside the I/O 255. TheFIFO 265 may be configured to receive data from one or more memory cells205 in the memory array 200. The FIFO 265 may be operable to correct forpropagation delays associated with receiving data from differentlocations. For example, the FIFO 265 may receive data from a firstmemory cell 205 having a first voltage and a first time delay and datafrom a second memory cell 205 having a second voltage and a second timedelay. The FIFO 265 may be configured to correct for propagation delaysassociated with receiving the data from the first memory cell and thesecond memory cell and outputting a stream of data including data fromboth the first memory and the second memory cell In some examples, anindividual FIFO cell (e.g., FIFO cell 265-a) may be selected to receivedata based on receiving an input signal. For example, the data bus 280may transfer the data to the FIFO cell 265-a at a limited swingsignaling or voltage—e.g., at a voltage lower than a voltage utilized bythe FIFO cell 265-a to process data associated with a logic state‘1’-when an input signal is received at FIFO cell 265-a. In someexamples, the limited swing voltage may enable the data bus 280 totransfer data at a voltage that is less than a voltage used bycomponents of the memory array 200 to process the data—e.g., a fullswing voltage. For example, the components of the memory array 200components may utilize approximately 1.1. volts to process dataassociated with a logic state ‘1.’ In the limited swing signalingexample, the data bus 280 may transfer the data associated with thelogic ‘1’ at approximately 0.5 volts—e.g., at a limited swing voltageless than the full swing voltage. Accordingly, the data bus 280 maytransfer data in the memory array 200 at a voltage less than the fullswing voltage to conserve current consumption. In such examples, theFIFO cell 265-a may have to recover the limited swing voltage receivedfrom the data bus 280 to the full swing voltage utilized by the FIFOcell 265-a to process the data. In some examples, the FIFO 265 may alsooutput data on bus 290 to the input/output 255—e.g., FIFO cell 265-a maybe selected based on an output signal received and output data onto bus290. In some examples, the bus 290 may also be a limited swing bus.

As described herein, the local memory controller 260 may be configuredto transmit a signal to a FIFO cell 265-a or FIFO cell 265-b to activateone or more precharge components 270 before the respective FIFO cell 265receives the data. In such examples, the one or more prechargecomponents 270 may precharge the respective FIFO cell 265 to a fullswing voltage (e.g., the voltage utilized by the respective FIFO cell265 to process data). For example, FIFO cell 265-a may be precharged tothe full swing voltage by precharge component 270-a. That is,precharging may refer to precharging one or more FIFO cells 265 to thefull voltage before receiving data at an input 275. Additionally, theFIFO 265 may also include an input 275 and output 285. In some examples,the input 275 or the output 285 may be external to the FIFO 265—e.g.,the input 275-a or output 285-a may be considered distinct from the FIFOcell 265-a. In some examples, the input 275-a may be an nMOS transistor—e.g., the transistor may pull down the voltage receive and not pull thevoltage up. In such examples, the FIFO cell 265-a may receive the datafrom the sense component 245 at a limited swing from the data bus 280.The transistor input 275-a may prevent voltage and power leaking fromthe FIFO cell 265-a to the data bus 280. In some examples, the gate ofthe nMOS transistor may be coupled with the input signal and select theFIFO cell 265-a based on receiving the input signal. Additionally, theFIFO cell 265-a may be operable to process the data at the full swingbased on the precharge. If the FIFO cell 265-a determines the dataprocessed is associated with the logic ‘1’, the FIFO cell 265-a maymaintain the high swing voltage. If the FIFO cell 265-a determines thedata processed is associated with a logic ‘0’, the FIFO cell 265-a maydischarge to a ground voltage.

In some examples, FIFO 265 may also be configurable to correct forpropagation delays between data received from the first memory cell anddata received from the second memory cell and output the data to thelocal memory controller 260. In some examples, FIFO 265 may beassociated with reading data. In other examples, FIFO 265 may beassociated with writing data. For example, memory controller 260 maysend data to the input/output 255 and through the FIFO 265 to the sensecomponent 245 and memory cells 205.

FIG. 3 illustrates an example of a circuit 300 that supports a datacircuit for a low swing data bus in accordance with examples asdisclosed herein. Circuit 300 may be an example of a FIFO cell 265(e.g., FIFO cell 265-a) as described with reference to FIG. 2. Circuit300 may include an input 310 (e.g., input 275 as described withreference to FIG. 2). In some examples, input 310 may include atransistor 315. Circuit 300 may include precharge components 320-a and320-b (e.g., precharge components 270 as described with reference toFIG. 2). Circuit 300 may include logic 330-a and output 340 (e.g.,output 285 as described with reference to FIG. 2). In some examples,circuit 300 may receive data 305 from one or more locations of a memoryarray (e.g., memory array 200 as described with reference to FIG. 2) ora memory device (e.g., memory device 110 as described with reference toFIG. 1). The circuit 300 may be coupled with a high-frequency bus (e.g.,data bus 280 or data bus 290 as described with reference to FIG. 2). Insome examples, the bus may be a limited swing bus as described withreference to FIGS. 1 and 2.

Input 310 may be configured to receive data 305. In some examples, input310 may receive data from a data bus (e.g., data bus 280 as describedwith reference to FIG. 1) coupled with the input 310. In some examples,the data bus may be operating a low swing voltage (e.g., at a firstvoltage lower than a second voltage associated with one or morecomponents of a memory array (e.g., a full swing voltage)). For example,the data bus may use a limited swing voltage when transferring dataassociated with a logic state (e.g., value) ‘1’. In other examples, thedata bus may be configured to transfer the data at a third voltage whenthe data is associated with a logic state ‘0’ (e.g., a VSS voltage at ornear a ground voltage). In some examples, the input 310 may beconfigured to receive the first voltage (e.g., the limited voltage) orthe third voltage (e.g., a voltage at or near ground). In some examples,input 310 may include an nMOS transistor 315, among other options orcombinations of components. In such examples, the nMOS transistor 315may be configured to pull down a voltage associated with the data305—e.g., the nMOS transistor 315 may not send a pull-up voltage (e.g.,a full swing voltage). In some examples, the nMOS transistor 315 mayoutput a voltage that is a difference between the input voltage and athreshold voltage of the nMOS transistor 315. As described withreference to FIG. 2, there may be an input 310 for each FIFO cell (e.g.,for each FIFO cell 265). For example, one or more (e.g., several)additional parallel inputs 310 of other FIFO cells may be in parallel tothe input 310 of circuit 300 as illustrated in FIG. 2. In such examples,each input 310 may be coupled with a different input signal—e.g., adifferent input signal as described with reference to FIG. 2. Forexample, the input 310 of circuit 300 may be coupled to a first inputsignal (input 0), an input 310 of a second FIFO cell may be coupled witha second input (input 1), and a third input 310 of a third FIFO cell maybe coupled with a third input (input 2). To select a respective input310, the circuit 300 may use an input pointer 350. For example, eachnMOS transistor 315 gate may be coupled to an input pointer 350configured to receive the respective input signal and the circuit 300may apply a voltage to the input pointer 350 to activate a respectiveinput 310 based on the FIFO cell selected—e.g., activate the input 310when receiving the first input signal at input pointer 350 asillustrated in FIG. 3 based on selecting circuit 300 (e.g., FIFO cell265-a).

Precharge components 320-a and 320-b may be configured to precharge thecircuit 300 to the second voltage (e.g., the full swing voltage) basedon receiving a signal 325. In some examples, the circuit 300 may beconfigured to process data associated with a respective logic state(e.g., a logic state ‘1’) at the second voltage. In such examples, thecircuit 300 may be configured to recover from the first voltage to thesecond voltage to process the data. Accordingly, the circuit 300 mayreceive a signal 325 (e.g., a precharge signal) at one or more prechargecomponents (e.g., precharge components 320-a and 320-b). In someexamples, the circuit 300 may receive the signal 325 before receivingthe data 305—e.g., the circuit 300 may precharge to the second voltagebefore receiving the data 305. In one example, precharge component 320-amay be a p-channel metal-oxide semiconductor (e.g., a pMOS) transistor.In such examples, precharge component 320-a may have a source coupledwith an output of the input 310 and a drain coupled with a logic 330-b.The gate of the precharge component 320-a may also receive the prechargesignal 325. In one example, precharge component 320-b may be a nMOStransistor. In such examples, the precharge component 320-b may have asource coupled with logic 330-b and a drain coupled with a groundvoltage (e.g., VSS). The gate of the precharge component 320-b mayreceive the precharge signal 325. In other examples, the prechargecomponent 320-a or precharge component 320-b may be a different type oftransistor (e.g., p-type or n-type transistor) or other components andcoupled at a different locations—e.g., the precharge components 320 maybe any components that drives the circuit 300 to the second voltage.

Logic 330-a and logic 330-b may be configured to store data 305, processdata 305, or otherwise perform digital calculations on data 305. Outputsignals 345-a and 345-b are used to output data from the circuit 300(e.g., FIFO cell 265-a) on a controlled timing without an delaydifferences—e.g., a new timing different than the input timing. In suchexamples, the circuit 300 may store the data at logic 330-a or logic330-b until the data is transferred to the output 340. In some examples,logic 330-a and logic 330-b may process data 305 associated with thelogic state ‘1’ at the second voltage and process data 305 associatedwith a logic state ‘0’ at the third voltage—e.g., the logic 330-a orlogic 330-b may store data associated with a logic state ‘0’ at avoltage at or near ground (e.g., VSS). That is, the circuit 300 maydischarge the second voltage to the third voltage based on receivingdata associated with the logic state ‘0’ as described with reference toFIG. 4.

Output 340 may be configured to output the data 305. In some examples,there may be multiple outputs 340 in parallel to the circuit 300 asdescribed with reference to FIG. 2—e.g., multiple outputs 340 forparallel FIFO cells 265. To select a respective output 340, the circuit300 may use an output pointer 345-a and 345-b. For example, the circuit300 may apply a voltage to the output pointer 345-a and output pointer345-b to activate a respective output 340 based on the FIFO cellselected—e.g., activate the output 340 illustrated in FIG. 3 based onselecting a first FIFO cell (e.g., FIFO cell 265-a).

In some examples, the circuit 300 may include a pMOS transistor 315 atthe input 310 rather instead of the nMOS transistor. In such examples,the system may transfer data 305 over the data bus at a limited swing toa full swing—e.g., the data bus may transfer data 305 associated with alogic ‘0’ at the limited swing voltage and data 305 associated withlogic ‘1’ at the full swing. In such examples, the bus may conservepower by reducing the current consumption to go from the half swing tothe full swing compared with going from no swing (e.g., ground) to fullswing. Accordingly, the input 310 may receive the second voltage (e.g.,voltage associated with transferring logic state ‘0’). The pMOStransistor 315 may pull up the second voltage instead of pull-down asdescribed with reference to the nMOS transistor 315. Additionally, whenthe circuit 300 utilizes the pMOS transistor 315, the prechargecomponents 320 may instead be discharge components. That is, the circuit300 may process the data 305 at a voltage (e.g., the third voltage)lower than the voltage associated with the data 305 (e.g., the secondvoltage). Accordingly, the circuit 300 may discharge from second voltageto the third voltage to process and/or store data 305 associated with alogic ‘0’.

By utilizing the input 310 and the precharge components 320, the circuit300 may be able to recover from a limited swing to the full swing toprocess the data (e.g., from the first voltage to the second voltage)without additional complicated CMOS circuitry. In such examples, asystem (e.g., system 100) may conserve power and concurrent bytransferring data over data busses at limited swing signaling andrecovering to full swing to process and handle the data 305. That is,the nMOS transistor 315 may prevent the circuit 300 voltage (e.g., theFIFO voltage) from leaking back to the data bus, enabling the system totransfer over the data bus at a limited swing voltage and recover thefull swing voltage at the circuit 300 to process the data.

FIG. 4 illustrates an example of a timing diagram 400 that supports adata circuit for a low swing data bus in accordance with examples asdisclosed herein. For example, the timing diagram 400 may illustrateoperations performed by circuit 300 and the components of the circuit300 as described with reference to FIG. 3 over time. The timing diagram400 illustrates examples of a circuit 300 receiving input pointersignals 405 (e.g., input signals at input pointer 350 as described withreference to FIG. 3), receiving data 420 (e.g., data 305 as describedwith reference to FIG. 3) and receiving output signals 425 (e.g., outputsignals 345 as described with reference to FIG. 3). The timing diagram400 may also show the circuit 300 receiving a precharge signal 410(e.g., precharge signal 325 as described with reference to FIG. 3). Thetiming diagram 400 may also illustrate a voltage of FIFO 415 (e.g.,circuit 300) voltage compared with the received data 420.

In some examples, the circuit 300 may receive input pointer signals 405as illustrated in FIG. 4. As described with reference to FIG. 3, arespective FIFO cell (e.g., FIFO cell 265-a as described with referenceto FIG. 2) may be selected to receive data based on the input pointersignal 405 being in a high state. For example, circuit 300 may beselected when the input pointer signal 405-a is received at a gate of annMOS transistor of an input of the FIFO cell—e.g., nMOS transistor 315of the input 310 as described with reference to FIG. 3.

In some examples, the circuit 300 may receive a precharge signal 410before receiving a respective input pointer signal 405. That is, asdescribed with reference to FIG. 3, circuit 300 may receive dataassociated with a logic state ‘1’ from the data bus at a limited swingvoltage (e.g., the bus level 420-b voltage). In such examples, thecircuit 300 may need to recover from the limited swing to a full swingvoltage (e.g., a voltage associated with processing data associated witha logic state ‘1’ at the FIFO circuit). That is, the circuit 300 mayutilize the precharge to compensate for the data bus using the limitedswing voltage.

For example, the circuit 300 may receive a precharge signal 410 at atime 425—e.g., at a time before receiving input pointer signal 405-b.The precharge signal 410 may activate one or more precharge components(e.g., precharge components 320 as described with reference to FIG. 3)and drive a voltage of the circuit 300 to a first voltage (e.g., theFIFO 415 voltage may go from ground to the full swing voltage). Afterthe precharge, the circuit 300 may receive the input pointer signal405-b. In some examples, after receiving the input pointer signal 405-b,the circuit 300 may receive data 420-a. In some examples, data 420-a maybe associated with a logic state ‘0.’ That is, the data bus (e.g., databus 280) may transmit data 420-a at a voltage (e.g., a second voltage)that is at or near a ground voltage. In such examples, the circuit 300may discharge and adjust the first voltage to the second voltage (e.g.,the ground voltage, VSS). The circuit 300 may process the data 420-a atthe second voltage and receive an output 425-a and output data 420-afrom the circuit 300—e.g., the circuit 300 may read a first logic state‘0’ based at least in part on precharging and discharging the FIFOcircuit.

Before receiving an input pointer signal 405-c and after receiving theoutput signal 425-a, the circuit 300 may receive a second prechargesignal 410. In some examples, in response to the second precharge signal410, circuit 300 may activate the one or more components and drive thecircuit 300 to the first voltage. After the precharge, circuit 300 mayreceive the input pointer signal 405-c based on the circuit 300 beingselected to receive data. In some examples, the circuit 300 may receivedata 420-b after receiving the input pointer signal 405-c. For example,the circuit 300 may receive data 420-b associated with a logic state‘1.’ That is, the data bus may transmit data 420-b at a third voltage(e.g., a limited swing voltage) associated with transferring dataassociated with a logic ‘1.’ In such examples, the circuit 300 maymaintain the first voltage—e.g., the FIFO 415 voltage may remain high atthe first voltage. As described with reference to FIG. 3, the circuit300 may avoid current leakage of the first voltage to the data bus 280based on an nMOS transistor (e.g., nMOS transistor 315 as described withreference to FIG. 3) at the input (e.g., input 310) of the circuit 300.In some examples, the circuit 300 may maintain the first voltage tostore the data 420-b. The circuit 300 may process the data 420-b at thefirst voltage and receive an output signal 425-b—e.g., the circuit 300may read a first logic state ‘1’ based at least in part on prechargingand maintaining the first voltage at the FIFO circuit and output thedata 420-b based on receiving the output signal 425-b.

In some examples, the timing diagram 400 may illustrate additionalvoltages of the bus and circuit 300 based on receiving additional inputpointer signals 405. For example, the circuit may receive a prechargesignal 410 before receiving input pointer signal 405-d. In someexamples, circuit 300 may already be at the first voltage—e.g., based onreceiving and processing data 420-b. In such examples, the FIFO 415 mayremain at the first voltage based on receiving the precharge signal 410.The data 420-b may be associated with the logic state ‘1’ based on thebus remaining at the third voltage. Circuit 300 may discharge based onreceiving data 420-c after receiving input signal pointer 405-e—e.g.,data 420-c received after input pointer signal 405-e may be associatedwith a logic state ‘0’ based on the data bus transmitting the secondvoltage (e.g., ground voltage). The circuit 300 may then receive anotherprecharge signal 410, precharge the circuit 300 to the first voltage(e.g., FIFO 415 may go high) and refrain from discharging based on data420-d being associated with a logic state ‘1’ after receiving inputpointer signal 405-f—e.g., the data bus may transmit the third voltage.By precharging the FIFO circuit each time before receiving data, thememory device may utilize a limited swing voltage on a data bus andrecover the limited swing voltage to the full swing at the FIFO circuitto process the data—e.g., by discharging or maintaining the prechargevoltage after receiving the data 420.

FIG. 5 shows a block diagram 500 of a memory device 520 that supports adata circuit for a low swing data bus in accordance with examples asdisclosed herein. The memory device 520 may be an example of aspects ofa memory device as described with reference to FIGS. 1 through 4. Thememory device 520, or various components thereof, may be an example ofmeans for performing various aspects of a data circuit for a low swingdata bus as described herein. For example, the memory device 520 mayinclude a precharge component 525, a receiving component 530, a voltageadjustment component 535, an operation component 540, or any combinationthereof. Each of these components may communicate, directly orindirectly, with one another (e.g., via one or more buses).

The precharge component 525 may be configured as or otherwise support ameans for precharging a first in first out (FIFO) circuit to a firstvoltage at. In some cases, the precharge component 525 may be configuredas or otherwise support a means for precharging the FIFO to the firstvoltage after adjusting the FIFO circuit to the second voltage. In somecases, the precharge component 525 may be configured as or otherwisesupport a means for receiving a precharge signal, where precharging theFIFO circuit is based at least in part on receiving the prechargesignal. In some examples, the precharge component 525 may be configuredas or otherwise support a means for activating a first transistorcoupled with an input of the FIFO to precharge the FIFO to the firstvoltage based at least in part on receiving the precharge signal.

The receiving component 530 may be configured as or otherwise support ameans for receiving, at the FIFO, a second voltage associated with oneor more components of a memory array and with transferring a first logicstate of a memory cell in the memory array over a data bus based atleast in part on precharging the FIFO to the first voltage. In someexamples, the receiving component 530 may be configured as or otherwisesupport a means for receiving, at the FIFO, a third voltage associatedwith one or more components of the memory array and with transferring asecond logic state of the memory cell over the data bus, where the thirdvoltage is less than a voltage associated with the second logic state.In some instances, the receiving component 530 may be configured as orotherwise support a means for receiving a voltage of the first logicstate is the second voltage.

The voltage adjustment component 535 may be configured as or otherwisesupport a means for adjusting the FIFO circuit to the second voltagebased at least in part on receiving the second voltage. In someinstances, the voltage adjustment component 535 may be configured as orotherwise support a means for maintaining the first voltage at the FIFObased at least in part on receiving the third voltage associated withtransferring the second logic state of the memory cell, wheremaintaining the first voltage is associated with storing the secondlogic state of the memory cell.

In some cases, the operation component 540 may be configured as orotherwise support a means for reading the first logic state receivedbased at least in part on precharging the FIFO. In some examples, theoperation component 540 may be configured as or otherwise support ameans for reading the second logic state received based at least in parton precharging the FIFO.

FIG. 6 shows a flowchart illustrating a method 600 that supports a datacircuit for a low swing data bus in accordance with examples asdisclosed herein. The operations of method 600 may be implemented by amemory device or its components as described herein. For example, theoperations of method 600 may be performed by a memory device asdescribed with reference to FIGS. 1 through 5. In some examples, amemory device may execute a set of instructions to control thefunctional elements of the device to perform the described functions.Additionally or alternatively, the memory device may perform aspects ofthe described functions using special-purpose hardware.

At 605, the method may include precharging a first in first out (FIFO)cell of a FIFO circuit to a first voltage. That is, the method mayinclude precharging a FIFO cell (e.g., FIFO cell 265-a) of a FIFOcircuit to the first voltage. The operations of 605 may be performed inaccordance with examples as disclosed herein. In some examples, aspectsof the operations of 605 may be performed by a precharge component 525as described with reference to FIG. 5.

At 610, the method may include receiving, at the FIFO, a second voltageassociated with one or more components of a memory array and withtransferring a first logic state of a memory cell in the memory arrayover a data bus based at least in part on precharging the FIFO to thefirst voltage. The operations of 610 may be performed in accordance withexamples as disclosed herein. In some examples, aspects of theoperations of 610 may be performed by a receiving component 530 asdescribed with reference to FIG. 5.

At 615, the method may include adjusting the FIFO circuit to the secondvoltage based at least in part on receiving the second voltage. Theoperations of 615 may be performed in accordance with examples asdisclosed herein. In some examples, aspects of the operations of 615 maybe performed by a voltage adjustment component 535 as described withreference to FIG. 5.

At 620, the method may include precharging the FIFO to the first voltageafter adjusting the FIFO circuit to the second voltage. The operationsof 620 may be performed in accordance with examples as disclosed herein.In some examples, aspects of the operations of 620 may be performed by aprecharge component 525 as described with reference to FIG. 5.

At 625, the method may include receiving, at the FIFO, a third voltageassociated with one or more components of the memory array and withtransferring a second logic state of the memory cell over the data bus,where the third voltage is less than a voltage associated with thesecond logic state. The operations of 625 may be performed in accordancewith examples as disclosed herein. In some examples, aspects of theoperations of 625 may be performed by a receiving component 530 asdescribed with reference to FIG. 5.

In some examples, an apparatus as described herein may perform a methodor methods, such as the method 600. The apparatus may include, features,circuitry, logic, means, or instructions (e.g., a non-transitorycomputer-readable medium storing instructions executable by a processor)for precharging a first in first out (FIFO) circuit to a first voltageat, receiving, at the FIFO, a second voltage associated with one or morecomponents of a memory array and with transferring a first logic stateof a memory cell in the memory array over a data bus based at least inpart on precharging the FIFO to the first voltage, adjusting the FIFOcircuit to the second voltage based at least in part on receiving thesecond voltage, precharging the FIFO to the first voltage afteradjusting the FIFO circuit to the second voltage, and receiving, at theFIFO, a third voltage associated with one or more components of thememory array and with transferring a second logic state of the memorycell over the data bus, where the third voltage is less than a voltageassociated with the second logic state.

Some examples of the method 600 and the apparatus described herein mayfurther include operations, features, circuitry, logic, means, orinstructions for maintaining the first voltage at the FIFO based atleast in part on receiving the third voltage associated withtransferring the second logic state of the memory cell, wheremaintaining the first voltage may be associated with storing the secondlogic state of the memory cell.

Some cases of the method 600 and the apparatus described herein mayfurther include operations, features, circuitry, logic, means, orinstructions for receiving a precharge signal, where precharging theFIFO circuit may be based at least in part on receiving the prechargesignal.

Some instances of the method 600 and the apparatus described herein mayfurther include operations, features, circuitry, logic, means, orinstructions for activating a first transistor coupled with an input ofthe FIFO to precharge the FIFO to the first voltage based at least inpart on receiving the precharge signal.

Some cases of the method 600 and the apparatus described herein mayfurther include operations, features, circuitry, logic, means, orinstructions for reading the first logic state received based at leastin part on precharging the FIFO and reading the second logic statereceived based at least in part on precharging the FIFO.

In some instances of the method 600 and the apparatus described herein,a voltage of the first logic state may be the second voltage.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, portions from two or more of the methods may be combined.

An apparatus is described. The apparatus may include a data busconfigured to transfer data at a first voltage different than a secondvoltage that is associated with one or more components of the memoryarray, a transistor coupled with the data bus and configured to receivethe first voltage from the data bus and to send a third voltage, and afirst in first out (FIFO) circuit coupled with the transistor andconfigured to receive the third voltage from the transistor, the FIFOcircuit including one or more precharge components configured to drivean input voltage of the FIFO circuit to the second voltage associatedwith the one or more components of the memory array based at least inpart on receiving the third voltage.

In some cases, the apparatus may include adjust the second voltage to afourth voltage associated with a ground based at least in part ondriving the input voltage to the second voltage.

In some instances, the apparatus may include receive a precharge signaland drive the input voltage of the FIFO circuit to the second voltagebased at least in part on receiving the precharge signal.

In some examples, the apparatus may include maintain the second voltageassociated with the logic state of the memory cell based at least inpart on storing the logic state at the FIFO circuit.

In some cases of the apparatus, the one or more precharge componentsinclude a second transistor coupled with the transistor and a firstvoltage source, the second transistor configured to drive the inputvoltage of the FIFO circuit based at least in part on receiving thethird voltage from the transistor and a third transistor coupled withthe first voltage source.

In some instances of the apparatus, the transistor may be an nMOStransistor and the first voltage may be less than the second voltage.

In some cases of the apparatus, the third voltage may be a differencebetween the first voltage and a threshold voltage of the nMOStransistor.

In some examples of the apparatus, the transistor in a pMOS transistorand the first voltage may be greater than the second voltage.

In some instances, the apparatus may include reduce the third voltage tothe second voltage.

In some cases of the apparatus, the second voltage associated with theone or more components of the memory array may be associated with alogic state of a memory cell of the memory array.

Another apparatus is described. The apparatus may include a data busconfigured to transfer data at a first voltage different than a secondvoltage associated with one or more components of the memory array, annMOS transistor configured to receive the first voltage over the databus and pull down the first voltage to a third voltage, and a first infirst out (FIFO) circuit coupled with the nMOS transistor and configuredto receive the third voltage from the nMOS transistor, the FIFOincluding one or more precharge components configured to drive an inputvoltage of the FIFO to the second voltage associated with the one ormore components of the memory array at least in part on receiving thethird voltage.

In some examples, the apparatus may include adjust the second voltage toa fourth voltage associated with a ground based at least in part ondriving the input voltage to the second voltage.

In some instances of the apparatus, the data bus may be furtherconfigured to transfer second data at a fourth voltage associated withthe one or more components of the memory array, the nMOS transistor maybe configured to receive the fourth voltage over the data bus and sendthe fourth voltage, and the FIFO circuit may be configured to adjust thesecond voltage to the fourth voltage based at least in part on receivingthe fourth voltage.

In some cases of the apparatus, the one or more precharge componentsfurther include a second transistor coupled with the nMOS transistor anda first voltage source, the second transistor configured to drive theinput voltage of the FIFO circuit based at least in part on receivingthe third voltage from the nMOS transistor and a third transistorcoupled with the first voltage source.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof. Some drawings may illustrate signals as a single signal;however, the signal may represent a bus of signals, where the bus mayhave a variety of bit widths.

The terms “electronic communication,” “conductive contact,” “connected,”and “coupled” may refer to a relationship between components thatsupports the flow of signals between the components. Components areconsidered in electronic communication with (or in conductive contactwith or connected with or coupled with) one another if there is anyconductive path between the components that can, at any time, supportthe flow of signals between the components. At any given time, theconductive path between components that are in electronic communicationwith each other (or in conductive contact with or connected with orcoupled with) may be an open circuit or a closed circuit based on theoperation of the device that includes the connected components. Theconductive path between connected components may be a direct conductivepath between the components or the conductive path between connectedcomponents may be an indirect conductive path that may includeintermediate components, such as switches, transistors, or othercomponents. In some examples, the flow of signals between the connectedcomponents may be interrupted for a time, for example, using one or moreintermediate components such as switches or transistors.

The term “coupling” refers to condition of moving from an open-circuitrelationship between components in which signals are not presentlycapable of being communicated between the components over a conductivepath to a closed-circuit relationship between components in whichsignals are capable of being communicated between components over theconductive path. When a component, such as a controller, couples othercomponents together, the component initiates a change that allowssignals to flow between the other components over a conductive path thatpreviously did not permit signals to flow.

The term “isolated” refers to a relationship between components in whichsignals are not presently capable of flowing between the components.Components are isolated from each other if there is an open circuitbetween them. For example, two components separated by a switch that ispositioned between the components are isolated from each other when theswitch is open. When a controller isolates two components, thecontroller affects a change that prevents signals from flowing betweenthe components using a conductive path that previously permitted signalsto flow.

The devices discussed herein, including a memory array, may be formed ona semiconductor substrate, such as silicon, germanium, silicon-germaniumalloy, gallium arsenide, gallium nitride, etc. In some examples, thesubstrate is a semiconductor wafer. In other examples, the substrate maybe a silicon-on-insulator (SOI) substrate, such as silicon-on-glass(SOG) or silicon-on-sapphire (SOP), or epitaxial layers of semiconductormaterials on another substrate. The conductivity of the substrate, orsub-regions of the substrate, may be controlled through doping usingvarious chemical species including, but not limited to, phosphorous,boron, or arsenic. Doping may be performed during the initial formationor growth of the substrate, by ion-implantation, or by any other dopingmeans.

A switching component or a transistor discussed herein may represent afield-effect transistor (FET) and comprise a three terminal deviceincluding a source, drain, and gate. The terminals may be connected toother electronic elements through conductive materials, e.g., metals.The source and drain may be conductive and may comprise a heavily-doped,e.g., degenerate, semiconductor region. The source and drain may beseparated by a lightly-doped semiconductor region or channel. If thechannel is n-type (i.e., majority carriers are electrons), then the FETmay be referred to as a n-type FET. If the channel is p-type (i.e.,majority carriers are holes), then the FET may be referred to as ap-type FET. The channel may be capped by an insulating gate oxide. Thechannel conductivity may be controlled by applying a voltage to thegate. For example, applying a positive voltage or negative voltage to ann-type FET or a p-type FET, respectively, may result in the channelbecoming conductive. A transistor may be “on” or “activated” when avoltage greater than or equal to the transistor's threshold voltage isapplied to the transistor gate. The transistor may be “off” or“deactivated” when a voltage less than the transistor's thresholdvoltage is applied to the transistor gate.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details toproviding an understanding of the described techniques. Thesetechniques, however, may be practiced without these specific details. Insome instances, well-known structures and devices are shown in blockdiagram form to avoid obscuring the concepts of the described examples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

For example, the various illustrative blocks and modules described inconnection with the disclosure herein may be implemented or performedwith a general-purpose processor, a DSP, an ASIC, an FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyprocessor, controller, microcontroller, or state machine. A processormay also be implemented as a combination of computing devices (e.g., acombination of a DSP and a microprocessor, multiple microprocessors, oneor more microprocessors in conjunction with a DSP core, or any othersuch configuration).

As used herein, including in the claims, “or” as used in a list of items(for example, a list of items prefaced by a phrase such as “at least oneof” or “one or more of”) indicates an inclusive list such that, forexample, a list of at least one of A, B, or C means A or B or C or AB orAC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase“based on” shall not be construed as a reference to a closed set ofconditions. For example, an exemplary step that is described as “basedon condition A” may be based on both a condition A and a condition Bwithout departing from the scope of the present disclosure. In otherwords, as used herein, the phrase “based on” shall be construed in thesame manner as the phrase “based at least in part on.”

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media cancomprise RAM, ROM, electrically erasable programmable read-only memory(EEPROM), compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave are included in the definition of medium. Disk and disc,as used herein, include CD, laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be apparent to those skilled in the art, and the generic principlesdefined herein may be applied to other variations without departing fromthe scope of the disclosure. Thus, the disclosure is not limited to theexamples and designs described herein, but is to be accorded thebroadest scope consistent with the principles and novel featuresdisclosed herein.

What is claimed is:
 1. An apparatus, comprising: a data bus configuredto transfer data at a first voltage different than a second voltage thatis associated with one or more components of a memory array, the firstvoltage based at least in part on a logic state of a memory cell of thememory array; a transistor coupled with the data bus and configured toreceive the data at the first voltage from the data bus and to send thedata at a third voltage; and a first in first out (FIFO) circuit coupledwith the transistor and comprising one or more precharge components, theFIFO circuit configured to: receive the data at the third voltage fromthe transistor; drive, using the one or more precharge components, aninput voltage of the FIFO circuit to the second voltage associated withthe one or more components of the memory array based at least in part onreceiving the data at the third voltage; and process, based at least inpart on the logic state of the memory cell and driving the input voltageof the FIFO circuit to the second voltage, the data at the secondvoltage or a fourth voltage different than the second voltage.
 2. Theapparatus of claim 1, wherein the FIFO circuit is further configured to:adjust the second voltage to the fourth voltage based at least in parton driving the input voltage to the second voltage, wherein the fourthvoltage is associated with a ground.
 3. The apparatus of claim 1,wherein the FIFO circuit is further configured to: receive a prechargesignal; and drive the input voltage of the FIFO circuit to the secondvoltage based at least in part on receiving the precharge signal.
 4. Theapparatus of claim 1, wherein the one or more precharge componentscomprise: a second transistor coupled with the transistor and a firstvoltage source, the second transistor configured to drive the inputvoltage of the FIFO circuit based at least in part on receiving the dataat the third voltage from the transistor; and a third transistor coupledwith the first voltage source.
 5. The apparatus of claim 1, wherein thetransistor is an nMOS transistor and the first voltage is less than thesecond voltage.
 6. The apparatus of claim 5, wherein the third voltageis a difference between the first voltage and a threshold voltage of thenMOS transistor.
 7. The apparatus of claim 1, wherein the transistor ina pMOS transistor and the first voltage is greater than the secondvoltage.
 8. The apparatus of claim 7, wherein, to drive the inputvoltage of the FIFO circuit, the one or more precharge components areconfigured to: reduce the third voltage to the second voltage.
 9. Theapparatus of claim 1, wherein the second voltage associated with the oneor more components of the memory array is associated with a logic stateof a memory cell of the memory array.
 10. An apparatus, comprising: adata bus configured to transfer data at a first voltage different than asecond voltage that is associated with one or more components of amemory array; a transistor coupled with the data bus and configured toreceive the first voltage from the data bus and to send a third voltage;and a first in first out (FIFO) circuit coupled with the transistor andcomprising one or more precharge components, the FIFO circuit configuredto: receive the third voltage from the transistor; drive, using the oneor more precharge components, an input voltage of the FIFO circuit tothe second voltage associated with the one or more components of thememory array based at least in part on receiving the third voltage; andmaintain the second voltage associated with a logic state of a memorycell of the memory array based at least in part on storing the logicstate at the FIFO circuit.
 11. A method, comprising: precharging a firstin first out (FIFO) circuit to a first voltage; receiving, at the FIFOcircuit, a second voltage associated with one or more components of amemory array and with transferring a first logic state of a memory cellin the memory array over a data bus based at least in part onprecharging the FIFO circuit to the first voltage; adjusting the FIFOcircuit to the second voltage based at least in part on receiving thesecond voltage; precharging the FIFO circuit to the first voltage afteradjusting the FIFO circuit to the second voltage; and receiving, at theFIFO circuit, a third voltage associated with one or more components ofthe memory array and with transferring a second logic state of thememory cell over the data bus, wherein the third voltage is less than avoltage associated with the second logic state.
 12. The method of claim11, further comprising: maintaining the first voltage at the FIFOcircuit based at least in part on receiving the third voltage associatedwith transferring the second logic state of the memory cell, whereinmaintaining the first voltage is associated with storing the secondlogic state of the memory cell.
 13. The method of claim 11, furthercomprising: receiving a precharge signal, wherein precharging the FIFOcircuit is based at least in part on receiving the precharge signal. 14.The method of claim 13, further comprising: activating a firsttransistor coupled with an input of the FIFO circuit to precharge theFIFO circuit to the first voltage based at least in part on receivingthe precharge signal.
 15. The method of claim 11, further comprising:reading the first logic state received based at least in part onprecharging the FIFO circuit; and reading the second logic statereceived based at least in part on precharging the FIFO circuit.
 16. Themethod of claim 11, wherein a voltage of the first logic state is thesecond voltage.
 17. An apparatus, comprising: a data bus configured totransfer data at a first voltage different than a second voltageassociated with one or more components of a memory array, the firstvoltage based at least in part on a logic state of a memory cell of thememory array; an nMOS transistor configured to receive the data at thefirst voltage over the data bus and pull down the first voltage to athird voltage; and a first in first out (FIFO) circuit coupled with thenMOS transistor and comprising one or more precharge components, theFIFO circuit configured to: receive the data at the third voltage fromthe nMOS transistor; drive an input voltage of the FIFO circuit to thesecond voltage associated with the one or more components of the memoryarray based at least in part on receiving the data at the third voltage;and process, based at least in part on the logic state of the memorycell, the data at the second voltage or a fourth voltage associated withground.
 18. The apparatus of claim 17, wherein the FIFO circuit isfurther configured to: adjust the second voltage to the fourth voltageassociated with the ground based at least in part on driving the inputvoltage to the second voltage.
 19. The apparatus of claim 17, whereinthe one or more precharge components further comprise: a secondtransistor coupled with the nMOS transistor and a first voltage source,the second transistor configured to drive the input voltage of the FIFOcircuit based at least in part on receiving the data at the thirdvoltage from the nMOS transistor; and a third transistor coupled withthe first voltage source.
 20. An apparatus, comprising: a data busconfigured to transfer data at a first voltage different than a secondvoltage associated with one or more components of a memory array; annMOS transistor configured to receive the first voltage over the databus and pull down the first voltage to a third voltage; and a first infirst out (FIFO) circuit coupled with the nMOS transistor and configuredto receive the third voltage from the nMOS transistor, the FIFO circuitcomprising one or more precharge components configured to drive an inputvoltage of the FIFO circuit to the second voltage associated with theone or more components of the memory array based at least in part onreceiving the third voltage, wherein: the data bus is further configuredto transfer second data at a fourth voltage associated with the one ormore components of the memory array; the nMOS transistor is configuredto receive the fourth voltage over the data bus and send the fourthvoltage; and the FIFO circuit is configured to adjust the second voltageto the fourth voltage based at least in part on receiving the fourthvoltage.